The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
An oxygen sensor may be positioned downstream from a catalytic converter to measure oxygen levels in exhaust gas produced by an engine. The oxygen levels and an air/fuel ratio of the engine may be determined based on an output voltage of the oxygen sensor. The oxygen sensor may output a rich voltage indicating a rich air/fuel ratio and the oxygen sensor may output a lean voltage indicating a lean air/fuel ratio.
Diagnostic systems may identify faults in the oxygen sensor based on a response time of the oxygen sensor. The response time of the oxygen sensor is the amount of time that the oxygen sensor takes to respond to a change in the oxygen levels at the oxygen sensor. The response time of the oxygen sensor typically increases over the life of the oxygen sensor. A faulty oxygen sensor may be identified when the response time of the oxygen sensor is greater than a predetermined time.